Effect of Adding Microwave Absorber on Structures and Properties of Hypercoal-Based Activated Carbons

Abstract

Using lignite-based hypercoal as raw material, KOH as activator and CuO as microwave absorber, we prepared hypercoal-based activated carbons by microwave-assisted activation. The pore structure and the electrochemical performance of the activated carbons were tested, and the effects of adding CuO in the activation reaction process were also investigated. The activated carbons prepared were characterized by nitrogen adsorption-desorption, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The specific surface area and mesoporous ratio of the hypercoal-based activated carbon are 1 257 m²/g and 55.4%, respectively. When the activated carbons are used as the electrode materials, the specific capacitance reaches 309 F/g in 3 M KOH electrolyte. In comparison with those prepared without CuO absorber, the specific capacitance increases by 11.6%. It was proved that the addition of microwave absorber in microwave-assisted activation was a low-cost method for rapidly preparing activated carbon, and it could effectively promote the development of the pore structure and improve its electrochemical performance.

Keywords

hypercoal / activated carbon / microwave absorber / pore structure / electrochemical performance

References

[1] Chen Y, Du L, Yang P, et al. Significantly Enhanced Robustness and Electrochemical Performance of Flexible Carbon Nanotube-Based Supercapacitors by Electrodepositing Polypyrrole. Journal of Power Sources, 2015, 287: 68-74.

[2] Das T, Chauhan H, Deka S, et al. Promising Carbon Nanosheet-Based Supercapacitor Electrode Materials from Low-Grade Coals. Microporous and MesoporousMaterials, 2017, 253: 80-90.

[3] Zhang Y, Yuan Z, Margni M, et al. Intensive Carbon Dioxide Emission of Coal Chemical Industry in China. Applied Energy, 2019, 236: 540-550.

[4] Dong Y, Jiang X, Ren M, et al. Environmental Implications of China’s Wind-Coal Combined Power Generation System. Resources, Conservation and Recycling, 2019, 142: 24-33.

[5] Chandaliya V K, Biswas P P, Dash P S, et al. Producing Low-Ash Coal by Microwave and Ultrasonication Pretreatment Followed by Solvent Extraction of Coal. Fuel, 2018, 212: 422-430.

[6] Liew R K, Azwar E, Yek P N Y, et al. Microwave Pyrolysis with KOH/NaOH Mixture Activation: A New Approach to Produce Micro-mesoporous Activated Carbon for Textile Dye Adsorption. Bioresource Technology, 2018, 266: 1-10.

[7] Xing B, Huang G, Chen L, et al. Microwave Synthesis of Hierarchically Porous Activated Carbon from Lignite for High Performance Supercapacitors. Journal of Porous Materials, 2016, 23(1): 67-73.

[8] Zhang M Y, Zhao X, Zhuang Q C. Preparation and Electrochemical Properties of Multiscale Porous Active Carbon for Supercapacitor Electrodes Made from Ultra-Pure Lignite by Microwave Irradiation. International Journal of Electrochemical Science, 2016, 11(3): 2 153-2 165.

[9] Yagmur E, Simsek K E H, Aktas Z, et al. Effect of CuO Receptor on the Liquid Yield and Composition of Oils Derived from Liquefaction of Coals by Microwave Energy. Energy Conversion and Management, 2008, 49(11): 3 043-3 050.

[10] Samanli S. A Comparison of the Results Obtained from Grinding in a Stirred Media Mill Lignite Coal Samples Treated with Microwave and Untreated Samples. Fuel, 2011, 90(2): 659-664.

[11] Liu H P, Chen T P, Li Y, et al. Temperature Rise Characteristics of ZhunDong Coal During Microwave Pyrolysis. Fuel Processing Technology, 2016, 148: 317-323.

[12] Monsef-Mirzai P, Ravindran M, McWhinnie W R, et al. Rapid Microwave Pyrolysis of Coal: Methodology and Examination of the Residual and Volatile Phases. Fuel, 1995, 74(1): 20-27.

[13] Feng B, Bhatia S K, Barry J C. Structural Ordering of Coal Char During Heat Treatment and Its Impact on Reactivity. Carbon, 2002, 40(4): 481-496.

[14] Zhou Q, Gao J, Li C, et al. Composite Organogels of Graphene and Activated Carbon for Electrochemical Capacitors. Journal of Materials Chemistry A, 2013, 1(32): 9 196-9 201.

[15] Zhao X Y, Huang S S, Cao J P, et al. KOH Activation of a Hypercoal to Develop Activated Carbons for Electric Double-Layer Capacitors. Journal of Analytical & Applied Pyrolysis, 2014, 105(5): 116-121.

[16] Koresh J, Soffer A. Stereoselectivity in Ion Electroadsorption and in Double-Layer Charging of Molecular Sieve Carbon Electrodes. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1983, 147(1–2): 223-234.

[17] Wang G, Zhang L, Zhang J. A Review of Electrode Materials for Electrochemical Supercapacitors. Chemical Society Reviews, 2012, 41(2): 797-828.

[18] Manjuraj T, Krishnamurthy G, Bodke Y D, et al. Synthesis, XRD, Thermal, Spectroscopic Studies and Biological Evaluation of Co (II), Ni (II) Cu (II) Metal Complexes Derived from 2-Benzimidazole. Journal of Molecular Structure, 2018, 1171: 481-487.

[19] Bianchi C, Datta A K, Dughiero F. Mechanistic Understanding of Plasma Arcing in Microwave Food Processing. Chemical Engineering Science, 2019, 195: 141-158.

[20] Zhang Y, Kang X, Tan J, et al. Influence of Calcination and Acidification on Structural Characterization of Anyang Anthracites. Energy & Fuels, 2013, 27(11): 7 191-7 197.

[21] Chen K, Liu F, Xue D, et al. Carbon with Ultrahigh Capacitance when Graphene Paper Meets K 3 Fe (CN) 6. Nanoscale, 2015, 7(2): 432-439.

[22] Li W, Zhu Y. Structural Characteristics of Coal Vitrinite During Pyrolysis. Energy & Fuels, 2014, 28(6): 3 645-3 654.

[23] Kaneko K, Ishii C, Rrike M, et al. Origin of Superhigh Surface Area and Microcrystalline Graphitic Structures of Activated Carbons. Carbon, 1992, 30(7): 1 075-1 088.

[24] Menendez J A, Arenillas A, Fidalgo B, et al. Microwave Heating Processes Involving Carbon Materials. Fuel Processing Technology, 2010, 91(1): 1-8.

[25] Ao W, Fu J, Mao X, et al. Microwave Assisted Preparation of Activated Carbon from Biomass: A Review. Renewable and Sustainable Energy Reviews, 2018, 92: 958-979.

[26] Wang Q, Cao Q, Wang X, et al. A High-Capacity Carbon Prepared from Renewable Chicken Feather Biopolymer for Supercapacitors. Journal of Power Sources, 2013, 225: 101-107.

[27] Kopyscinski J, Rahman M, Gupta R, et al. K₂CO₃ Catalyzed CO2 Gasification of Ash-Free Coal. Interactions of the Catalyst with Carbon in N₂ and CO₂ Atmosphere. Fuel, 2014, 117(1): 1 181-1 189.

[28] He X, Lei J, Geng Y, et al. Preparation of Microporous Activated Carbon and Its Electrochemical Performance for Electric Double Layer Capacitor. Journal of Physics and Chemistry of Solids, 2009, 70(3–4): 738-744.

[29] Xu Z, Yuan Z, Zhang D, et al. Highly Mesoporous Activated Carbon Synthesized by Pyrolysis of Waste Polyester Textiles and MgCl₂: Physiochemical Characteristics and Pore-Forming Mechanism. Journal of Cleaner Production, 2018, 192: 453-461.

[30] Guo Y, Shi Z, Chen M, et al. Hierarchical Porous Carbon Derived from Sulfonated Pitch for Electrical Double Layer Capacitors. Journal of Power Sources, 2014, 252: 235-243.

[31] Hastak R S, Sivaraman P, Potphode D D, et al. High Temperature All Solid State Supercapacitor Based on Multi-Walled Carbon Nanotubes and Poly [2, 5 Benzimidazole]. Journal of Solid State Electrochemistry, 2012, 16(10): 3 215-3 226.

[32] Gao X, Xing W, Zhou J, et al. Superior Capacitive Performance of Active Carbons Derived from Enteromorpha Prolifera. Electrochimica Acta, 2014, 133: 459-466.

[33] Kim T Y, Jung G, Yoo S, et al. Activated Graphene-Based Carbons as Supercapacitor Electrodes with Macro- and Mesopores. ACS Nano, 2013, 7(8): 6 899-6 905.

[34] You C, Yan X, Kong J, et al. Direct Electrochemistry of Myoglobin Based on Bicontinuous Gyroidal Mesoporous Carbon Matrix. Electrochemistry Communications, 2008, 10(12): 1 864-1 867.